Light. The last socially accepted pollution?

Friday 26th November 2021

The Environment Act has become law, COP26 has been and gone. Progress has been made on addressing the climate and biodiversity crisis, with still some way to go. However, despite wide-ranging discussions, one form of pollution has snuck past our world leaders and policy makers, despite it being in plain sight. Light pollution is accepted, not even considered perhaps, as a form of pollution, yet by the definition of pollution, it fits the bill.

Photo – RENDERING of the Glasgow installation indestructible language by Mary Ellen Carroll, MEC studios © 2021 Drone photo by Dougie Lindsay

Artificial night lighting is one of the most pervasive – and yet under-recognised – causes of environmental pollution. The State of Nature, State of Nature Partnership, 2019.

Boris Johnson Green Light

Global light pollution has increased by at least 49% over 25 years. The rapid switch to cheap LEDs is contributing to the installation of more, brighter lights, in homes, public spaces, roads and businesses. Artificial Light at Night (ALAN) is now directly linked to measurable negative impacts on wildlife, human health, and energy consumption.

Artificial light has been a socially accepted norm since the advent of fire, you can even consider it one of the first forms of pollution. Lighting has advanced rapidly in the last century, in 2014 Blue LEDs were even awarded the Nobel Prize of Physics, celebrated for “Filling the world with new light”. Despite this, in many ways, our concern for the impact of light on our own lives is built into our daily habits. Modern screens include automatic features for ‘nightshift’, or ‘eye-saver’ modes. Blackout blinds and curtains keep out lights at night allowing us better sleep. So why do we give such little consideration to the way artificial light is impacting our natural environment?

Evidence on the impacts of light pollution on invertebrates continues to be published. This year results from the first study to show long-term negative impacts of light pollution on moth populations was published, revealing that caterpillar populations can be reduced by 52% in areas with streetlights. A further study discovered that light pollution forces a change in dung beetle behaviour. While research shows that lifelong exposure to ALAN is impacting the chirping of crickets.

ALAN also affects wildlife beyond invertebrates, such as bats, birds, reptiles, amphibians, mammals, and even plants. We must treat it with more consideration.


Just because a light is energy efficient, doesn’t mean it is good for the planet. Development in lighting has good intentions to reduce energy and increase durability. However, evidence points towards benefits being missed with an increased number of lights, more places lit up and even greater costs on energy. Focusing solely on energy credentials in lighting is unfortunately just another form of greenwashing.

Light continues to be seen as fair game, it is extensively used in advertising, artwork, events and displays. Seen as an affordable and eco-friendly way to get messages across or provide temporary installations, the negative impacts are overlooked. Using light in the wrong places, particularly protected habitats, no matter how brief the time can have detrimental effects. Public lighting events can set bad examples and provide the message that it is okay to light up the world. Lighting to call for action on climate and nature also suggests that, if the ‘environmentalists’ are doing it, then there can’t be a problem. Picture the same messages being shared on single-use plastic paraphernalia instead – there would be condemnation.

National Trust/Bute Park/ Luminate Wales

We should not solely focus on the energy-saving benefits of certain lights, we must consider that some lights are unnecessary, wasteful, and are polluting the natural environment When installing lighting for any reason, it is vital to consider the immediate habitat being polluted, if there are measures to mitigate the lighting they should be taken.

Accepting that light is a form of pollution

Society does recognise light as pollution. Whenever there is an astronomical event, such as a meteor shower, geomagnetic storm, or comet, for example, advice on how and where to see it often casually includes – “find a spot away from light pollution.” We must now take that acceptance and know that we can do something about it. In much the same way the public has campaigned for waters free from sewage, we can now campaign for skies free from unnecessary artificial light.

Light is a unique pollutant in that it can be reduced with every flick of a switch. We can decrease how much light we emit yet continue our activities that require artificial light. This makes it an exciting opportunity for politicians and individuals alike. In a world with growing eco-anxiety, we can take simple steps for the good of the planet and at very little cost.

Climate Clock in Glasgow counting down to COP26 – Copyright Andrew Boyd

There is hope. Ahead of the second stage of COP15, the drafted framework includes an ambition to prevent and reduce light pollution. Proposals from The European Union, Namibia, and New Zealand, as well as the Center for Biological Diversity, and the Convention on Migratory Species, include steps to reduce light pollution. We are encouraging world leaders, in particular the UK Government to avoid the oversights of the past and confront light pollution and its impacts on biodiversity. Thanks to the efforts of Buglife, the Environment Minister has already promised to explore the issue and the steps Defra can take with other Government departments and bodies. We are also working on other policy measures that could address light pollution, such as new planning frameworks in England and Scotland, and the Environment Strategy in Northern Ireland.

The solutions are simple, and the message is clear, use light effectively rather than lavishly.

Buglife are campaigning to reduce the impacts of artificial light on invertebrates and other wildlife. To read more about our campaign and find out some of the steps you can take to reduce your own light pollution, visit our light pollution page.